978595561 has 2 divisors, whose sum is σ = 978595562. Its totient is φ = 978595560.

The previous prime is 978595549. The next prime is 978595577. The reversal of 978595561 is 165595879.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 663320025 + 315275536 = 25755^2 + 17756^2 .

It is an emirp because it is prime and its reverse (165595879) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 978595561 - 2⁵ = 978595529 is a prime.

It is not a weakly prime, because it can be changed into another prime (978595511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 489297780 + 489297781.

It is an arithmetic number, because the mean of its divisors is an integer number (489297781).

Almost surely, 2^978595561 is an apocalyptic number.

It is an amenable number.

978595561 is a deficient number, since it is larger than the sum of its proper divisors (1).

978595561 is an equidigital number, since it uses as much as digits as its factorization.

978595561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3402000, while the sum is 55.

The square root of 978595561 is about 31282.5120634517. The cubic root of 978595561 is about 992.8136673316.

The spelling of 978595561 in words is "nine hundred seventy-eight million, five hundred ninety-five thousand, five hundred sixty-one".